The Commens Dictionary
Quote from ‘Reason's Rules’
…a proposition is not a single thing and cannot properly be said to have any existence. Its mode of being consists in its possibility. A proposition which might be expressed has all the being that belongs to propositions although nobody ever expresses it or thinks it. It is the same proposition every time it is thought, spoken, or written, whether in English, German, Spanish, Tagálog, or how. A proposition consists in a meaning, whether adopted or not, and however expressed. That meaning is the meaning of any sign which should signify that a certain iconic representation, or image, (or any equivalent of it) is a sign of something indicated by a certain indexical sign, or any equivalent thereof. To illustrate this, any sentence will answer.
…every proposition is capable of expression either by means of a photograph, or composite photograph, with or without stereoscopic or cinetoscopic elaborations, together with some sign which shall show the connections of these images with the object of some index, or sign or experience, forcing the attention, or bringing some information, or indicating some possible source of information; or else by means of an analogous icon appealing to other senses than that of sight, together with analogous forceful indications, and a sign connecting the icon with these indices. [—]
A proposition is the signification of a sign which represents that an icon is applicable to that which an index indicates.